Fridays with Finn

An Equine Nutrition Blog

What you need to know about omega-3s?

By: Madeline Boast, MSc. Equine Nutrition

Why Feed Omega 3s?

In equine nutrition, there is a big push for feeding omega-3s with all sorts of fancy oils on the market. The main underlying metabolic mechanism is that omega 3s are an anti-inflammatory fatty acid. These are required for basic physiological functions and are key components of many tissues and organs. In addition to their anti-inflammatory properties, they can also help with coat health.

Research supports the supplementation of omega-3 fatty acids as there is evidence to suggest supplementation could help to manage many chronic conditions such as osteoarthritis, laminitis, and equine metabolic syndrome. It is also suggested that they can help increase the longevity of performance horses.

Other than the clearly reported health benefits, they can be a great way to increase the caloric content of the diet without increasing grain products. Omega-3 rich oils are calorically dense and as long as they are introduced to the diet slowly can make fantastic energy sources.


The O3 to O6 ratio

Both omega-3s and omega-6s are essential in the diet. However, the ratio is important as horses often have too many omega-6s due to grains in the diet. This can be problematic because omega-6s support pro-inflammatory pathways, whereas omega-3s support anti-inflammatory pathways. Currently, we do not know the ideal ratio of omega-3s to omega-6s. However, forages and lush pasture have higher omega-3s so it is hypothesized that the omega-3 content of the diet should exceed the omega-6 content.

Marketing has done a great job at turning omega-6s into the “bad guys”, but in fact, they are also required to support regular body function. Omega-6s are key components of inflammatory pathways – and inflammation is required to heal. That’s right, not all inflammation is bad. The reason that you want to avoid an exacerbated level of omega-6s in the diet is to avoid horses having an exaggerated inflammatory response. When there is excess inflammation, it contributes to an array of performance limiting issues.


The Different Types

Recognizing the different types of omega-3s and 6s is important prior to being able to choose a supplement in an evidence-based way. The metabolic pathway of omega-3s and 6s both begin with a parent molecule. For the O6s this is linoleic acid (LA) and for the O3s this is alpha-linoleic acid (ALA). In order for these molecules to be altered into fatty acids that are further down the metabolic pathway they both must use the enzyme delta 6 desaturase. This is a liver enzyme, and it elongates ALA into SDA before the horse is able to synthesize DHA.

Since they both use the same enzyme, it is rate limiting as there is only so much available and they must compete for its use. There is evidence of this conversion rate being low, particularly with the conversion of ALA to EPA and DHA which are metabolites further down the pathway. Below is a simplified diagram showing the process:

When to Supplement

There are a few common issues that I see with the availability of omega-3s in equine diets. First, is that many owners do not know that pasture is a great source of omega-3s, and after all, this is what the horse has evolved to consume. Unfortunately, in Ontario, providing pasture year-round is not feasible and many farms do not have the land resources to have horses housed on pasture all summer. A second issue is that when grains are incorporated into the diet they provide a significant amount of omega-6s. Therefore, occasionally, supplementation of omega-3s to optimize the O3 to O6 ratio is recommended.


Choosing An Omega-3 Source

When choosing a supplement, I first and foremost recommend ensuring that the fat source you are providing is not high in omega-6s. Once you have that established, I recommend having a nutritionist evaluate your horse’s diet to see if it is high in omega-6s. If your horse’s current diet is high in omega-6s, and you are looking for a calorically dense supplement this is when I turn to the more expensive commercial omega-3 oils.

When looking for an omega-3 supplement, it is important you are choosing one that provides the correct omega-3s. Not only do you want DHA, but you also want omega-3s that can readily be converted (skipping the rate limiting step) such as SDA.

Fish oil is a very well recognized source of both SDA and DHA, however, it can be problematic when supplemented to horses as they are herbivores and the palatability of fish oil is low. Plant oils vary greatly in omega-3 fatty acid content. Below is a chart that compares the O3 and O6 content of various feed ingredients:

Now, what about some of the commercial oils that are marketed to have EPA and DHA? Research does illustrate clear benefits to DHA supplementation, so in certain situations spending the extra money on these is likely beneficial. However, every situation is unique and having your horse’s diet evaluated by an equine nutritionist can help you decide.

To conclude, when deciding on a supplement, what really matters is your goal. Are you trying to level out a high omega-6 ratio? Are you trying to increase caloric content? Are you trying to combat chronic inflammation? Each of these situations will have a different ideal supplement.

If you have any questions simply email me at 


Goh, Y. M., Mohd-Azam, G. K., Sia, I. Y., Shri, K., & Law, E. L. (2004). Plasma n-3 and n-6 fatty acid profiles and their correlations to hair coat scores in horses kept under Malaysian conditions. Jurnal Veterinar Malaysia, 16(1&2), 31-37.

Hess, T. M., Rexford, J. K., Hansen, D. K., Harris, M., Schauermann, N., Ross, T., ... & Mulligan, C. M. (2012). Effects of two different dietary sources of long chain omega-3, highly unsaturated fatty acids on incorporation into the plasma, red blood cell, and skeletal muscle in horses. Journal of animal science, 90(9), 3023-3031.

Hess, T., & Ross-Jones, T. (2014). Omega-3 fatty acid supplementation in horses. Revista Brasileira de Zootecnia, 43, 677-683.

Kronfeld, D. S. (1996). Dietary fat affects heat production and other variables of equine performance, under hot and humid conditions. Equine veterinary journal, 28(S22), 24-34.

Manhart, D. R., Scott, B. D., Gibbs, P. G., Coverdale, J. A., Eller, E. M., Honnas, C. M., & Hood, D. M. (2009). Markers of inflammation in arthritic horses fed omega-3 fatty acids. The Professional Animal Scientist, 25(2), 155-160.

Melo, S., Wanderley, E., Diniz, I., Manso, H., & Manso Filho, H. (2014). Oil Supplementation Produces an Increase in Antioxidant Biomarkers in Four‐Beat Gaited Horses. Equine Veterinary Journal, 46, 32-33.

Mel'uchová, B., Blaško, J., Kubinec, R., Górová, R., Michalec, M., Vargová, V., ... & Soják, L. (2009). Influence of floristic grazing cover on sheep milk quality. Acta fytotechnica et zootechnica, 12(3), 57-64.

Nogradi, N., Couetil, L. L., Messick, J., Stochelski, M. A., & Burgess, J. R. (2015). Omega‐3 fatty acid supplementation provides an additional benefit to a low‐dust diet in the management of horses with chronic lower airway inflammatory disease. Journal of Veterinary Internal Medicine, 29(1), 299-306.

Woodward, A. D., Nielsen, B. D., O'Connor, C. I., Skelly, C. D., Webel, S. K., & Orth, M. W. (2007). Supplementation of dietary long-chain polyunsaturated omega-3 fatty acids high in docosahexaenoic acid (DHA) increases plasma DHA concentration and may increase trot stride lengths in horses. Equine and Comparative Exercise Physiology, 4(2), 71-78.


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